Exemplary embodiments of the invention relate to a separator arrangement.
For various applications of separators, in particular in the area of medical or food technology or milk processing, centrifuge drums are arranged and operated in a chamber having negative pressure in relation to the surrounding area.
European patent document EP 1 119 416 B1 discloses a generic separator arrangement comprising a separator drum for liquid/liquid/solid separation, which has a vertical rotational axis and which is arranged in a sealed receptacle or hooded chamber in which negative pressure in relation to the surrounding area is able to be generated by way of a pump. The separator drum comprises a feed pipe and one or several impellers for discharging the one or several liquid phases as well as solid matter discharge openings for continuously or intermittently discharging solid matter.
The generic structure and its method of operation have proved their worth.
Nevertheless there is a requirement for further improvement of the known separator arrangement and of the method for the operation thereof.
According to one aspect of the invention at least the drive chamber is put under negative pressure in relation to the surrounding area, in particular, in order to achieve an energy saving on rotating parts of the region.
For this purpose, negative pressure in relation to the surrounding area is generated completely or at all events in a part region in the chamber that includes components of the drive device—in particular components of the motor, coupling, spindle, bearing and/or other drive components.
To this end, the drive chamber region can be evacuated by way of a pump or another device that generates negative pressure and/or it is connected to the (hooded) chamber surrounding the drum such that a pump or a corresponding device, which, where applicable, generates a vacuum additionally in the chamber, is also able to generate a vacuum in the drive chamber “at the same time”. When the hooded chamber in which the drum is arranged is also put under negative pressure in relation to the surrounding area, an energy saving can also be achieved here too.
It is particularly advantageous according to one variant, which also forms an independent invention, to have a negative pressure connection on a particularly large radius in the hooded chamber as in this case the drum rotation has a supporting effect on the generation of the vacuum. In this case, both the drum and the hooded chamber are preferably realized in portions in a conical manner.
One variant for a negative pressure connection can be a connection via a bore in the spindle. In this case, the free end of the spindle is guided downward through the sealed frame wall and the attaching to a negative pressure system is effected via sealed connections. The bore in the spindle ends in the region below the drum in the hooded chamber. The feed through of the spindle through the frame wall is also sealed by means of mechanical elements.
Conventional impellers are suitable as liquid drainage outlets in the drum. However, also conceivable is sealing/insulating the centripetal pump/drum by means of a submerging disk.
The non-continuously utilizable laboratory centrifuge of Japanese patent document JP 32 58 359 A can also be named as part of the technological background, where the products to be centrifuged are received in sample vessels such that the product is well protected during centrifuging.
Using a liquid-cooled, in particular oil-cooled or water-cooled, motor is particularly advantageous.
It appears advantageous to arrange the oil-lubricating system, in particular a circular lubricating system, also in the vacuum region, in particular with one or several of the following features:                oil circulating pump in the vacuum region        oil container in the vacuum region,        heat exchanger (for oil circuit) in the vacuum region.        
A coolant supply through the drum (in the manner of German patent document DE 19922237) also appears advantageous.
It is additionally particularly advantageous when in operation negative pressure below atmospheric pressure, in particular 0.3 bar less than this, preferably 0.4 bar less than this, in particular 0.7 bar less than this, is generated.
It is additionally advantageous when the value of the negative pressure is modified at all events in the hooded chamber with the drum during operation in dependence on the operating state. This, once again, is an advantageous invention. Thus, for example, in time prior to, during or after a modification in the operating state, the negative pressure can also be modified. In this case, the modification in the operating state, which is modified prior to, during or after the modification in the negative pressure, can be a solid matter ejection. For example, the negative pressure can be somewhat increased briefly prior to or at least during the ejection (e.g. from 0.2 bar to 0.5 bar) and lowered again after the ejection (e.g. back to 0.2 bar) so that no disadvantageous effects occur during a solid matter ejection on account of the high negative pressure.
According to a further advantageous variant, the modification in the operating state, for example, prior to, during or after the modification in the negative pressure, can be an incoming or outgoing/discharge phase.
The invention is particularly suitable for a separator arrangement with a separator having a drum with a vertical rotational axis, which is placed onto a rotatable drive spindle and is surrounded by a hood, the drum comprising a drum diameter greater than 500 mm, in particular 800 mm, in a quite especially preferred manner greater than 900 mm and/or speeds for example greater than 8000 rpm, 5000 rpm, 4000 rpm in operation.
The circumferential speed at the drum outside diameter is preferably at least 100 m/s or more.
The surface of the drum is additionally preferably between 0.5 m2 and 5 m2, in particular 1-3.5 m2 such that the action of supporting the negative pressure generation has a particularly advantageous effect.